Not all is fair in love and war in Sebastian Faulks' novels. In his best known and most loved work, "Birdsong," a young Englishman is torn from a passionate affair with a married woman and plunged into the roiling carnage of World War I. In its loosely linked World War II sequel, "Charlotte Gray," the eponymous Scottish heroine goes in search of her missing lover in occupied France and becomes active with the Resistance.

More recently Faulks' fiction has been preoccupied with the stuff of life: exploring the ways lives intersect in "A Possible Life" and, in "Where My Heart Used to Beat," grappling with the weighty issues of "What is a life? What is it worth?"

Faulks' latest novel, "Paris Echo," sees him covering both bases — harking back to complex relationships in wartime France, and along the way asking what knowledge and sacrifices are necessary to lead a meaningful life.

The book unfolds through the first-person accounts of two non-Parisians. We meet 19-year-old Tariq, who leaves Tangier for the French capital to live "like a hero" and discover more about where his mother grew up. There is also American scholar Hannah, who is in town to research the lives of women in Paris under the German Occupation.

Hannah gives the Moroccan runaway shelter; in return, Tariq assists her with translating oral testimonies. When not immersed in her studies, Hannah reflects on a burnt-out love affair, oblivious to a friend's amorous advances. Tariq ventures out and becomes something of a flâneur, making solitary tours through the city's streets and alleys on foot, or traveling its tunnels on the Métro while getting a crash course in its history from a puppeteer called Victor Hugo. After sifting several cautionary tales, Hannah gradually develops a new lease of life; once sampling what Paris has to offer, Tariq comes to realize "how many different ways there were of being alive."

This is a profound and moving novel about two disparate people forgetting their differences, pooling their resources and appreciating the world afresh in a remarkable city. Paris is so well mapped and chronicled that it emerges as a third character. Faulks prudently resists presenting a soft-focus tourist-friendly depiction. Tariq's peregrinations take him into the shabbier migrant suburbs and into the shadows of Algerian conflict. Hannah's forays into the past unearth stories of courage and fortitude but also of betrayal, complicity and injustice — one of which chills her and challenges her moral outlook.

Now and again Faulks deviates from his customary realist approach by adding surreal flourishes: ghostly encounters, time-warped dislocation, out-of-body experiences. Some readers will see this as a bold move, others as a cheap trick. Far less divisive is his full-bodied, multifaceted characterization, and his intelligent insights into the effect of the past on the present. As Hannah argues, "History was not a pageant; it was real and now."

Malcolm Forbes has written for the Times Literary Supplement, the Economist and the Daily Beast. He lives in Edinburgh, Scotland.

Paris Echo
By: Sebastian Faulks.
Publisher: Henry Holt, 258 pages, $27.